1. Field of the Invention
The field of art to which this invention pertains may be generally located in the class of devices relating to land vehicles. Class 280, Land Vehicles, United States Patent Office Classification, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Description of the Prior Art
This invention relates generally to intermediate deck structures for use in vehicles, for example, truck and trailer vans, railway cars, freight containers, and the like. Heretofore, various types of intermediate deck structures have been proposed for supporting freight articles of various shapes and weights above the horizontal bed or floor of a transport van, and the like, in order to increase the load carrying ability of a van and to maximize the use of the available cubic capacity of a van. The U.S. Pat. No. 3,911,832 to Vandergriff discloses a prior art intermediate deck structure for use in railway cars, truck and trailer vans, and the like, and which includes a first section pivotally connected at its outer end to one side wall of a vehicle, or the like, and which is adapted to be pivoted between a stored vertical position adjacent said one side wall of a vehicle and a horizontal operative loading position with its inner end extending inwardly from said side wall. A second section of the Vandergriff intermediate deck has a pair of arms extended from its inner end which are pivotally connected to the first section at a point between the inner and outer ends thereof. The second section of the intermediate deck is adapted to be stored adjacent said one side wall of the vehicle below the first section of the intermediate deck in a position extending downwardly from the outer end of a stored first section. The second section is adapted to be pivoted relative to the first section during pivoting of the first section to a horizontal loading position, whereby the second section can also be moved to a horizontal loading position with the outer end of the second section supported by a pair of load brackets engaged with a load rail on the opposite side wall of the vehicle. A problem encountered when the last described intermediate deck structure is used is that when the two deck sections are stored against said one side wall of the vehicle the load bracket on the second section extends downwardly to a position where it can interfere with and damage cargo and boxes sitting on the main floor of the vehicle. When the intermediate deck structure is in a horizontal loading position, it is also subject to being accidentally hit and damaged, and because of no reinforcement means to resist side impacts, the load brackets are bent, by the fork members of a fork truck in the process of loading and unloading a vehicle. The load brackets are also subject to damage if the deck second section falls or swings down to a point where the load brackets hit the floor of a vehicle.
A further problem inherent in the Vandergriff intermediate deck is that it can not be used on trailer vans which have wheel boxes that are movable relative to a trailer van floor, but which are fixed relative to the trailer van wheels and axles, so that the trailer van can be raised up by an air lift suspension to bring the trailer van floor and top of the wheel boxes level with a loading dock to permit fork lift loading and unloading, since the movement of such wheel boxes would be interfered with by the low stored second section of the intermediate deck. Still another problem encountered in the use of the aforementioned Vandergriff intermediate deck is that the inner ends of the tubes forming the side frame members of the second deck sections are seated in the inside of the inner ends of the channels forming the side frame members of the first section, and said inner ends of said tubes exert a concentrated pressure on said inner ends of said first section channels which results in many instances in extruded metal fatigue and breaking of the inner ends of the first section channels. The same inherent metal fatigue problem exists on the extreme edge of said tubes where the load bracket on the inside is cantilevered outward so the load bracket hooks can meet the slots in the wall load track rail. A further problem encountered in the use of the aforementioned prior art intermediate deck is that the load brackets employed in said intermediate deck structure are subject to jumping out of the wall load track rail slots, causing the load brackets to retract under a load on the deck, and dropping the load onto the cargo positioned underneath the intermediate deck.